Summary of Work: Depressive symptoms have been represented as both episodic and an enduring individual difference in the research and clinical literature. We investigated the structure of depressive symptoms longitudinally in a sample of older adults. Participants were 737 (MAge = 73 years initially, 39% women) individuals in the Baltimore Longitudinal Study of Aging (BLSA) who provided biennial data on up to 5 occasions over an 8 year period. There was evidence for both trait and state variability, with symptoms increasing longitudinally. Trait-like variability accounted for at least two-thirds of the reliable variance and no carry-over effects were found across the two year intervals considered here. Interindividual differences remained constant over time, but how much individuals differed from themselves diminished across occasions. Age trends in the five factors and 30 facets assessed by the Revised NEO Personality Inventory in Baltimore Longitudinal Study of Aging data (N = 1,944; 5,027 assessments) were examined in data collected between 1989 and 2004. Analyses showed that retest stability was uniformly high throughout adulthood, birth cohort effects were modest, and there were no consistent Gender ?e Age interactions. Consistent with cross-sectional results, HLM analyses showed modest personality changes in adulthood: a decline up to age 80 in Neuroticism, stability and then decline in Extraversion, decline in Openness, increase in Agreeableness, and increase up to age 70 in Conscientiousness. A small subset of individuals showed non-normative changes that might be due to genetic factors, disease, or life experience.